A speaker device that outputs a sound (voice) with a predetermined frequency band is known. Among such speaker devices, some speaker devices have a configuration in which an actuator is provided with, for example, a vibrating element, such as a piezoelectric element and a magnetostrictive element, and the expansion and contraction of the vibrating element causes a vibrator, such as a vibrating plate, to vibrate to output a sound (see, for example, Patent Document 1).
According to the speaker device described in Patent Document 1, a driving signal is input to the vibrating element to cause it to expand and contract, and the expansion and contraction of the vibrating element causes the vibrator to vibrate to output a sound.
Such a speaker device is able to offer a large driving force, and is therefore able to ensure a fine sound output state.